Ski bike



FIG. 1 is a right side elevational view of a ski bike showing my new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a top elevational view thereof;

FIG. 4 is a bottom view thereof;

FIG. 5 is a rear view thereof; and,

FIG. 6 is a left side elevational view thereof. 

The ornamental design for a ski bike, as shown and described. 